1. Field of the Invention
This invention relates to ergonomic supports, especially lumbar supports, for seats, particularly for automobile seats.
2. Related Art
Modern seat designs commonly include lumbar supports for the comfort of the person sitting in the seat. In fact, it is becoming more common for seats to incorporate a variety of components for passenger comfort, including heating and cooling ducts and the like. The promulgation of components within the confines of a seat creates a need for smaller, more compact components. Saving space is also served by reducing the number of components required to provide ergonomic support.
It is desirable in designing ergonomic controls for automobile seats to minimize the amount of manual effort a passenger needs to exert to move an ergonomic device such as a lumbar support through its full range of travel. A large number of turns required on a manual hand-crank or lever are undesirable. Generally speaking, prior art combinations of lumbar supports and actuators had a one-to-one ratio of actuator motion relative to lumbar support motion. For example, a traction cable would need to be pulled 10 millimeters in order to move a lumbar support attached to it 10 millimeters closer to a passenger. There is a need in the art for a lumbar support that increases the ratio of pressure surface travel to actuator movement.
It is also desirable for ergonomic devices in automobile seats to be actuated by the lightest, and consequently least expensive, actuator components. Accordingly, it is desirable for a lumbar support configuration to reduce the load on actuators. There is a need for an ergonomic support whose configuration gives mechanical advantage to the actuator, so that lighter and less expensive actuator cables, gears, motors, etc. may be used.
The most common current form of prior art lumbar support is a traction actuated arching basket such as those described in U.S. Pat. No. 5,397,164. This type of lumbar support uses traction to arch a flexible pressure surface towards the passenger by increasing the convexity of the bowed shape of the pressure surface. These pressure surfaces are naturally biased towards a flat position. The natural bias must be overcome by the traction device. Accordingly, there is an additional load that must be overcome by the actuator. In addition to the load created by the weight of the passenger, these prior art lumbar devices have to overcome the load of flexing the pressure surface, and overcome the friction inherent in sliding the moving ends of such arching lumbar supports along their stationary mounts. There is a need in the art for a lumbar support configuration that eliminates unnecessary loads.
Some lumbar supports move up and down in the seat to raise and lower the point of support. Such supports must overcome the friction of moving along the seat cushions. There is a need to eliminate such friction.
Another disadvantage of arching lumbar supports is that as the pressure surface extends farther towards the passenger, the surface area contacting the passenger shrinks, which is less comfortable. The pressure surface also becomes more rigid at its furthest extension, which is also uncomfortable. There is a need for a lumbar support that retains its full effective surface area and flexibility when extended.
Furthermore, in the particular art of supporting the lumbar spine, there is a need for spinal relief. That is, the bony vertebrae of the spine become uncomfortable if direct pressure is applied to them by a lumbar support pressure surface. It is preferable to apply lumbar supporting pressure bilaterally adjacent to the spinal column, while maintaining a vertical recess or channel to accommodate the vertebrae.
As with all auto parts, there is a constant need in seat assembly procedures to increase the economy, speed and efficiency of component assembly and shipping. There is a further need in seat design for strong, economical, compact components.
Producing fewer parts serves these needs. Nevertheless, the device must remain strong and stay robust through many cycles of use.